Automotive beam axles often consist of a central carrier assembly with axle tubes connectedly extending outwardly from the carrier assembly toward wheels. The central carrier assembly commonly comprises a sealed housing and cover disposed around a differential assembly. The differential assembly includes a plurality of gears and is configured to couple an input shaft, also known as a drive-shaft, to two output shafts, also known as axle-shafts. Proximal ends of the two axle-shafts are commonly coupled to the differential within the carrier and extend through the axle tubes outwardly through wheel bearings and retainers/seals near distal ends of the axle-shafts. Hub assemblies are commonly attached to the end of the axle tubes and connect the distal ends of the axle-shafts to the wheels.
The axle tubes are commonly connected to the frame of the vehicle via suspension components. The beam axle is configured to support a portion of the weight of the vehicle, also known as the sprung mass of the vehicle. The transfer path of the sprung mass may travel from the frame through the suspension components, through the axle tubes and carrier, through the axle-shafts and differential, and into the wheels which contact the ground. The term wheels, as used here, also may include tires.
Axle carriers for these applications are designed to withstand both torsional and suspension loads and are often substantial in size and weight. Axle carriers for these applications are also designed to hold lubrication fluids for the differential and at least portions of the input and output shafts or components that transfer rotation/torque between the differential and input and output-shafts. Weight and fluid level reduction on these designs is often difficult. Solutions which reduce fluid volume commonly increase weight, and solutions which minimize weight commonly increase fluid volume. Increased difficulty may be added by the differences in parting line orientations between the inside core and external mold for the housing of the carrier.